(100 days)
The intended use of the Al6 is the measurement of arterial blood flow by means of venous occlusion plethysmography. The Al6 replaces the predicate instruments which are used primarily in research studies. Applications include studies that relate to protocols that influence limb blood flow through exercise, reactive hyperemia, or the influence of drugs.
The intended use of the Al6 is the measurement of blood flow by means of venous occlusion plethysmography. This is the same usage as one of the uses of our EC6 Plethysmograph and it has not changed.
The Al6 Blood Flow Measuring system measures blood flow in one or two limbs or digits simultaneously using the principles of venous occlusion plethysmography. This involves inflating a blood pressure cuff on the proximal part of the limb to a pressure that exceeds the venous pressure in the limb, but which is less than the arterial pressure. The cuff inflation is done quickly so as to obtain a distinct starting point for the measurement. When the cuff is inflated the limb begins to swell due to the blood flowing into the limb since the normal venous outflow is stopped by the cuff. The resulting change in the volume of the limb is measured by the plethysmographs and the rate of change is equal to the blood flow at the moment of venous occlusion. The Al6 is controlled by a computer program that causes the cuff inflators to inflate, records the plethysmographic volume measurements and calculates the rate of change of volume. By combining the instruments and controlling them with one computer it is possible to make measurements in quick succession and more easily analyze the results.
The provided documentation describes the Hokanson Blood Flow Measuring System (AI6), but it does not contain a typical acceptance criteria table with reported device performance metrics against specific thresholds. Instead, the submission focuses on demonstrating equivalence to predicate devices through comparisons of key components and their performance.
Here's a breakdown of the requested information based on the provided text, highlighting where information is present and where it is absent:
1. Table of acceptance criteria and the reported device performance
As mentioned, a formal table of acceptance criteria with specific performance metrics and their corresponding thresholds is not present in the provided document. The submission assesses performance relative to predicate devices.
| Feature Assessed | Predicate Device Comparison | Reported AI6 Performance |
|---|---|---|
| Accuracy of Strain Gauge Plethysmographs | Same technology and strain gauges as predicate device (EC6 Plethysmograph, K982707). | "equal to the EC6 predicate device." |
| Accuracy of Pressure Regulators | Same pressure regulator as predicate device. | "identical to that of the predicate device." |
| Pressure Accuracy (Venous Occlusion Cuff) | Not explicitly compared as a separate predicate characteristic, but the predicate device also performs venous occlusion plethysmography. | "within plus or minus 1 mmHg." (Note: requirement for venous occlusion pressure is 15-100 mmHg; 50-60 mmHg usually chosen) |
| Speed of Inflation | Tubing identical to predicate device (E20, K905367). Valves have slightly higher Cv than predicate device. | "equal to that of the predicate device." Largest cuff inflates from 0 to 50 mmHg in less than 300 mSec, which is less than one heartbeat. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
This information is not provided in the document. The submission describes bench testing and comparisons to predicate devices, not studies involving human subjects or specific data sets.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This information is not applicable/provided. The evaluation described is based on engineering and performance characteristics of components, not on expert-adjudicated ground truth from a test set of medical data.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This information is not applicable/provided. There is no mention of a test set requiring adjudication in the context of this submission.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
A MRMC study was not conducted. This device is a measurement system and does not involve AI assistance for human readers or interpretation of medical images.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
This is a physical medical device (Blood Flow Measuring System) that performs measurements. While it is computer-controlled, it's not an "algorithm only" device in the sense of an AI diagnostic tool. The description focuses on its standalone measurement capabilities as equal to combined predicate devices. Therefore, the functional performance of the device itself can be considered standalone, but it's not an AI algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" for this submission is based on physical constants, engineering specifications, and the established performance of the predicate devices. For example, pressure accuracy is measured against a known standard (mmHg), and inflation speed is measured against a known time (mSec). The core claim is that since the components and their performance are equivalent to legally marketed predicate devices, the new device is also safe and effective.
8. The sample size for the training set
This information is not applicable/provided. This device does not use machine learning or AI algorithms that require a "training set."
9. How the ground truth for the training set was established
This information is not applicable/provided as there is no training set for an AI algorithm.
§ 870.2780 Hydraulic, pneumatic, or photoelectric plethysmographs.
(a)
Identification. A hydraulic, pneumatic, or photoelectric plethysmograph is a device used to estimate blood flow in a region of the body using hydraulic, pneumatic, or photoelectric measurement techniques.(b)
Classification. Class II (performance standards).